The move was last night branded “outrageous and penny-pinching” by campaigners who pointed out that law firms representing the soldiers’ Iraqi and Afghan accusers have had their cases funded by legal aid.

Mrs May met the heads of the Army, Navy and RAF, as well as the chief of defence staff, and told them that she would not allow “abuse of the legal system” by law firms bringing cases against British soldiers.

Theresa May met with military advisersCredit:
Steve Back/Barcroft Images

A complex criminal trial defence would run into tens of thousands of pounds. In contrast, law firms representing Iraqi civilians who have accused troops of war crimes and other serious offences have been paid millions of pounds in legal aid to bring cases against them.

Politicians who sent the troops to war are entitled to claim their legal costs from the taxpayer for any legal action brought against them by families of dead soldiers, under established protocols.

The MoD confirmed that the legal costs of troops taken to court would not automatically be paid.

The MoD is funding multi-million pound inquiries into soldiers’ actions in Iraq and Afghanistan but they are hair-splitting over the money for solicitors’ costsHilary Meredith, solicitor

Nigel Kelsall, who runs the UK Veterans One Voice campaign group, said: “The Government is quite happy to send troops overseas to war, but then quite happy to prosecute the troops who are just doing their jobs.

“Legal costs should be paid by the Ministry of Defence. It is outrageous and penny-pinching that they don’t.”

Rules on funding for military personnel facing courts martial are governed by a complex set of criteria laid out in an obscure defence notice.

The MoD can pay a defendant’s legal costs, but can also choose not to do so “if the department believes that the individual was acting outside the scope of his or her employment”.

British troops in Basra in 2006Credit:
David Cheskin /PA

The Armed Forces runs its own legal aid system, and just as with civilian legal aid, military suspects are means tested before they qualify for free or subsidised defence lawyers.

In almost all cases, serving soldiers earn more than the legal aid minimum, ruling them out of a free defence lawyer. Those who have a disposable income of between £12,475 and £37,500 may be entitled to some contribution towards costs. That contribution is calculated by the Armed Forces Criminal Legal Aid Authority.

I don’t understand how Number 10 can claim soldiers are being supported through the judicial processJohnny Mercer, Conservative MP

Hilary Meredith, a solicitor whose clients include a major facing prosecution for manslaughter in Iraq, said: “Why are we holding our servicemen to the same principles as common criminals?

"The MoD is funding multi-million pound inquiries into soldiers’ actions in Iraq and Afghanistan but they are hair-splitting over the money for solicitors’ costs.”

The Iraq Historic Allegations Team (Ihat) is investigating almost 1,500 cases of mistreatment and unlawful killings in Iraq. The major would be the first person prosecuted on the recommendation of Ihat.

On Monday, a spokesman for Theresa May said it was “right that we continue to support anyone from the Armed Forces involved in an investigation or inquiry and they will receive appropriate support, including legal advice where necessary”.

Johnny Mercer MP served in the armed forces

Johnny Mercer, a Conservative MP and former soldier who has called for criminal investigations into alleged abuses in Iraq and Afghanistan to be scrapped, said: “I don’t understand how Number 10 can claim soldiers are being supported through the judicial process. I can only assume the Prime Minister was not personally involved in the issuing of this statement.”

An MoD spokesman said: “All those interviewed after caution in Ihat investigations have received publicly-funded legal advice and assistance.

“If their case is referred to trial, they are eligible to apply for support and our dedicated legal aid body would contact them to ensure they receive what they are entitled to – the MoD can, in appropriate cases, decide to fund legal support at trial without means testing.”